This invention relates to tools used for restoring the original contour of sheet metal, particularly that contained in the bodies of vehicles such as automobiles, trucks, aircraft, trailers, boats and the like.
Dent-removing hand tools are well-known in the prior art because it is frequently necessary to remove concave dents from panels and fenders of motor vehicles. This is sometimes possible by hammering from the rear or by filling the dents with a material such as metal or plastic which is later leveled to produce a smooth surface.
It is frequently difficult, however, to obtain access to the rear of dented panels because door panels, fenders and other structures are often enclosed or the rear is otherwise obstructed. Repair techniques involving fillers are time-consuming and expensive.
Consequently, a number of conventional tools have been developed to remove concave dents. Perhaps best known among these tools is a slide hammer or "slap" hammer with a screw-end. The screw-end is first embedded in a hole in the panel, and pulling force is then applied by rapidly sliding a weight or hammer along a rod away from the screw and against a stop on the end of the rod opposite the screw. Typical of such prior slide hammers are the ones described in U.S. Pat. Nos. 3,030,837 and 3,570,289. Such devices damage the panel being repaired by leaving a screw hole in it. Consequently, it has previously been suggested that a suction cup, as illustrated in FIG. 3 of U.S. Pat. No. 3,570,289, be substituted for the screw in a slide hammer dent removing tool.
By contrast, U.S. Pat. No. 3,584,836 illustrates a dent remover which uses a suction cup having a port through which a vacuum is drawn. The cup is pulled by a chain attached to the middle of the cup and to a hydraulicly actuated stanchion. While U.S. Pat. No. 3,584,836 offers some advantages by utilizing a suction cup from which air is drawn by external means, it is a large, expensive, cumbersome structure which is not well adapted to removal of dents on all vehicle-body orientations or to convenient, speedy use.